Protection from malicious apps?

While the process that Apple uses to review apps on it's Appstore has come under a lot of criticism (and justifiably so), the one thing that developers and users can't argue with is the fact that Apple takes a lot of care to ensure that malicious apps do not make their way into the store. Apple ensures that apps that request access to certain device services and user data are scrutinized very closely and seldom approved.

The Android Market on the the other hand seems a lot more open and I wonder don't know if there is a published process that describes the kind of review process apps go through before developers are allowed to list them on the store. How do we know that a seemingly innocent app that displays weather data isn't also accessing my stored passwords and email and sending them off to a server in Russia?